Merge pull request #69 from rfjakob/next

Changes for 1.8.1

.gitignore

@@ -34,6 +34,8 @@ Makefile.in
 /po/remove-potcdate.sed
 /po/Makefile.in.in
 /po/Rules-quot
+/po/*.gmo
+/po/stamp-po
 
 /m4/*.m4
 !/m4/ax_boost_base.m4

ChangeLog

@@ -1,3 +1,23 @@
+Sun Mar 22 2015 Jakob Unterwurzacher <[email protected]>
+ * release version 1.8.1
+ * reverse: re-enable kernel cache (bug #60)
+ * reverse mode: disable unique IV by default
+ * add "make benchmark-reverse"
+ * remove "-o default_permissions" to improve performance
+
+Fri Mar 20 2015 Eric Swanson <[email protected]>
+ * add option "--require-macs" (bug #14)
+
+Fri Mar 13 2015 Valient Gough <[email protected]>
+ * add po files to git (bug #63)
+
+Mon Mar 9 2015 Jakob Unterwurzacher <[email protected]>
+ * release version 1.8
+ * improve automatic test converage: also test reverse mode (make test)
+ * add automatic benchmark (make benchmark)
+ * compare MAC in constant time ( fixes bug #12 )
+ * lots of fixes to make building on OSX easier
+
 Sun Nov 23 2014 Jakob Unterwurzacher <[email protected]>
  * add per-file IVs to reverse mode
  * add --nocache option

Makefile.am

@@ -26,3 +26,8 @@ test-verbose:
 .PHONY: benchmark
 benchmark:
  sudo tests/benchmark.pl /var/tmp
+
+.PHONY: benchmark-reverse
+benchmark-reverse:
+ tests/benchmark-reverse.pl /var/tmp
+ tests/benchmark-reverse.pl /var/tmp --nocache

configure.ac

@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 
-AC_INIT([encfs], [1.8])
+AC_INIT([encfs], [1.8.1])
 AC_CONFIG_SRCDIR([encfs/encfs.h])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])

encfs/FileUtils.cpp

@@ -855,14 +855,21 @@ static bool boolDefaultYes(const char *prompt) {
 /**
  * Ask the user whether to enable block MAC and random header bytes
  */
-static void selectBlockMAC(int *macBytes, int *macRandBytes) {
- // xgroup(setup)
- bool addMAC = boolDefaultNo(
- _("Enable block authentication code headers\n"
- "on every block in a file? This adds about 12 bytes per block\n"
- "to the storage requirements for a file, and significantly affects\n"
- "performance but it also means [almost] any modifications or errors\n"
- "within a block will be caught and will cause a read error."));
+static void selectBlockMAC(int *macBytes, int *macRandBytes, bool forceMac) {
+ bool addMAC = false;
+ if (!forceMac) {
+ // xgroup(setup)
+ addMAC = boolDefaultNo(
+ _("Enable block authentication code headers\n"
+ "on every block in a file? This adds about 12 bytes per block\n"
+ "to the storage requirements for a file, and significantly affects\n"
+ "performance but it also means [almost] any modifications or errors\n"
+ "within a block will be caught and will cause a read error."));
+ } else {
+ cout << _("\n\nYou specified --require-macs. "
+ "Enabling block authentication code headers...\n\n");
+ addMAC = true;
+ }
 
  if (addMAC)
  *macBytes = 8;
@@ -893,13 +900,13 @@ static void selectBlockMAC(int *macBytes, int *macRandBytes) {
 /**
  * Ask the user if per-file unique IVs should be used
  */
-static bool selectUniqueIV() {
+static bool selectUniqueIV(bool default_answer) {
  // xgroup(setup)
- return boolDefaultYes(
+ return boolDefault(
  _("Enable per-file initialization vectors?\n"
  "This adds about 8 bytes per file to the storage requirements.\n"
  "It should not affect performance except possibly with applications\n"
- "which rely on block-aligned file io for performance."));
+ "which rely on block-aligned file io for performance."), default_answer);
 }
 
 /**
@@ -977,15 +984,16 @@ RootPtr createV6Config(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  Interface nameIOIface; // selectNameCoding()
  int blockMACBytes = 0; // selectBlockMAC()
  int blockMACRandBytes = 0; // selectBlockMAC()
- bool uniqueIV = false; // selectUniqueIV()
- bool chainedIV = false; // selectChainedIV()
+ bool uniqueIV = true;  // selectUniqueIV()
+ bool chainedIV = true;  // selectChainedIV()
  bool externalIV = false; // selectExternalChainedIV()
  bool allowHoles = true; // selectZeroBlockPassThrough()
  long desiredKDFDuration = NormalKDFDuration;
 
  if (reverseEncryption) {
  chainedIV = false;
  externalIV = false;
+ uniqueIV = false;
  blockMACBytes = 0;
  blockMACRandBytes = 0;
  }
@@ -1009,8 +1017,6 @@ RootPtr createV6Config(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  nameIOIface = BlockNameIO::CurrentInterface();
  blockMACBytes = 8;
  blockMACRandBytes = 0; // using uniqueIV, so this isn't necessary
- uniqueIV = true;
- chainedIV = true;
  externalIV = true;
  desiredKDFDuration = ParanoiaKDFDuration;
  } else if (configMode == Config_Standard || answer[0] != 'x') {
@@ -1021,15 +1027,10 @@ RootPtr createV6Config(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  keySize = 192;
  blockSize = DefaultBlockSize;
  alg = findCipherAlgorithm("AES", keySize);
- blockMACBytes = 0;
- externalIV = false;
  nameIOIface = BlockNameIO::CurrentInterface();
- uniqueIV = true;
 
- if (reverseEncryption) {
- cout << _("reverse encryption - chained IV disabled") << "\n";
- } else {
- chainedIV = true;
+ if (opts->requireMac) {
+ blockMACBytes = 8;
  }
  }
 
@@ -1052,15 +1053,15 @@ RootPtr createV6Config(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  nameIOIface = selectNameCoding();
  if (reverseEncryption) {
  cout << _("reverse encryption - chained IV and MAC disabled") << "\n";
- uniqueIV = selectUniqueIV();
+ uniqueIV = selectUniqueIV(false);
  /* Reverse mounts are read-only by default (set in main.cpp).
  * If uniqueIV is off, writing can be allowed, because there
  * is no header that could be overwritten */
  if (uniqueIV == false)
  opts->readOnly = false;
  } else {
  chainedIV = selectChainedIV();
- uniqueIV = selectUniqueIV();
+ uniqueIV = selectUniqueIV(true);
  if (chainedIV && uniqueIV)
  externalIV = selectExternalChainedIV();
  else {
@@ -1070,7 +1071,7 @@ RootPtr createV6Config(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  << "\n";
  externalIV = false;
  }
- selectBlockMAC(&blockMACBytes, &blockMACRandBytes);
+ selectBlockMAC(&blockMACBytes, &blockMACRandBytes, opts->requireMac);
  allowHoles = selectZeroBlockPassThrough();
  }
  }
@@ -1500,6 +1501,12 @@ RootPtr initFS(EncFS_Context *ctx, const shared_ptr<EncFS_Opts> &opts) {
  shared_ptr<EncFSConfig> config(new EncFSConfig);
 
  if (readConfig(opts->rootDir, config) != Config_None) {
+ if (config->blockMACBytes == 0 && opts->requireMac) {
+ cout
+ << _("The configuration disabled MAC, but you passed --require-macs\n");
+ return rootInfo;
+ }
+
  if (opts->reverseEncryption) {
  if (config->blockMACBytes != 0 || config->blockMACRandBytes != 0 ||
  config->externalIVChaining ||

encfs/FileUtils.h

@@ -88,6 +88,8 @@ struct EncFS_Opts {
 
  bool readOnly; // Mount read-only
 
+ bool requireMac; // Throw an error if MAC is disabled
+
  ConfigMode configMode;
 
  EncFS_Opts() {
@@ -104,6 +106,7 @@ struct EncFS_Opts {
  configMode = Config_Prompt;
  noCache = false;
  readOnly = false;
+ requireMac = false;
  }
 };
 

encfs/encfs.pod

@@ -121,6 +121,15 @@ password. If this succeeds, then the filesystem becomes available again.
 Do not mount the filesystem when encfs starts; instead, delay mounting until
 first use. This option only makes sense with B<--ondemand>.
 
+=item B<--require-macs>
+
+If creating a new filesystem, this forces block authentication code headers to
+be enabled. When mounting an existing filesystem, this causes encfs to exit
+if block authentication code headers are not enabled.
+
+This can be used to improve security in case the ciphertext is vulnerable to
+tampering, by preventing an attacker from disabling MACs in the config file.
+
 =item B<--reverse>
 
 Normally B<EncFS> provides a plaintext view of data on demand. Normally it
@@ -134,7 +143,7 @@ For example, the following would create an encrypted view in /tmp/crypt-view.
  encfs --reverse /home/me /tmp/crypt-view
 
 You could then copy the /tmp/crypt-view directory in order to have a copy of
-the encrypted data. You must also keep a copy of the file /home/me/.encfs5
+the encrypted data. You must also keep a copy of the file /home/me/.encfs6.xml
 which contains the filesystem information. Together, the two can be used to
 reproduce the unencrypted data:
 
@@ -145,6 +154,14 @@ Now /tmp/plain-view contains the same data as /home/me
 Note that B<--reverse> mode only works with limited configuration options, so
 many settings may be disabled when used.
 
+=item B<--nocache>
+
+Disable the kernel's cache of file attributes.
+Setting this option makes EncFS pass "attr_timeout=0" and "entry_timeout=0" to
+FUSE. This makes sure that modifications to the backing files that occour
+outside EncFS show up immediately in the EncFS mount. The main use case
+for "--nocache" is reverse mode.
+
 =item B<--standard>
 
 If creating a new filesystem, this automatically selects standard configuration

encfs/main.cpp

@@ -57,6 +57,12 @@
 extern "C" void fuse_unmount_compat22(const char *mountpoint);
 #define fuse_unmount fuse_unmount_compat22
 
+/* Arbitrary identifiers for long options that do
+ * not have a short version */
+#define LONG_OPT_ANNOTATE 513
+#define LONG_OPT_NOCACHE 514
+#define LONG_OPT_REQUIRE_MAC 515
+
 using namespace std;
 using namespace rlog;
 using namespace rel;
@@ -190,6 +196,7 @@ static bool processArgs(int argc, char *argv[],
  out->opts->useStdin = false;
  out->opts->annotate = false;
  out->opts->reverseEncryption = false;
+ out->opts->requireMac = false;
 
  bool useDefaultFlags = true;
 
@@ -215,15 +222,16 @@ static bool processArgs(int argc, char *argv[],
  {"delaymount", 0, 0, 'M'}, // delay initial mount until use
  {"public", 0, 0, 'P'}, // public mode
  {"extpass", 1, 0, 'p'}, // external password program
- // {"single-thread", 0, 0, 's'}, // single-threaded mode
- {"stdinpass", 0, 0, 'S'}, // read password from stdin
- {"annotate", 0, 0, 513},  // Print annotation lines to stderr
- {"nocache", 0, 0, 514}, // disable caching
+ // {"single-thread", 0, 0, 's'},  // single-threaded mode
+ {"stdinpass", 0, 0, 'S'},  // read password from stdin
+ {"annotate", 0, 0, LONG_OPT_ANNOTATE}, // Print annotation lines to stderr
+ {"nocache", 0, 0, LONG_OPT_NOCACHE}, // disable caching
  {"verbose", 0, 0, 'v'}, // verbose mode
  {"version", 0, 0, 'V'}, // version
  {"reverse", 0, 0, 'r'}, // reverse encryption
  {"standard", 0, 0, '1'}, // standard configuration
  {"paranoia", 0, 0, '2'}, // standard configuration
+ {"require-macs", 0, 0, LONG_OPT_REQUIRE_MAC}, // require MACs
  {0, 0, 0, 0}};
 
  while (1) {
@@ -255,9 +263,12 @@ static bool processArgs(int argc, char *argv[],
  case 'S':
  out->opts->useStdin = true;
  break;
- case 513:
+ case LONG_OPT_ANNOTATE:
  out->opts->annotate = true;
  break;
+ case LONG_OPT_REQUIRE_MAC:
+ out->opts->requireMac = true;
+ break;
  case 'f':
  out->isDaemon = false;
  // this option was added in fuse 2.x
@@ -295,8 +306,11 @@ static bool processArgs(int argc, char *argv[],
  * filesystem where something can change the underlying
  * filesystem without going through fuse can run into
  * inconsistencies."
- * Enabling reverse automatically enables noCache */
- case 514:
+ * However, disabling the caches causes a factor 3
+ * slowdown. If you are concerned about inconsistencies,
+ * please use --nocache. */
+ break;
+ case LONG_OPT_NOCACHE:
  /* Disable EncFS block cache
  * Causes reverse grow tests to fail because short reads
  * are returned */
@@ -359,13 +373,6 @@ static bool processArgs(int argc, char *argv[],
 
  if (!out->isThreaded) PUSHARG("-s");
 
- if (useDefaultFlags) {
- PUSHARG("-o");
- PUSHARG("use_ino");
- PUSHARG("-o");
- PUSHARG("default_permissions");
- }
-
  // we should have at least 2 arguments left over - the source directory and
  // the mount point.
  if (optind + 2 <= argc) {
@@ -388,6 +395,26 @@ static bool processArgs(int argc, char *argv[],
  }
  }
 
+ // Add default flags unless --no-default-flags was passed
+ if (useDefaultFlags) {
+
+ // Expose the underlying stable inode number
+ PUSHARG("-o");
+ PUSHARG("use_ino");
+
+ // "default_permissions" comes with a performance cost. Only enable
+ // it if makes sense.
+ for(int i=0; i < out->fuseArgc; i++) {
+ if ( out->fuseArgv[i] == NULL ) {
+ continue;
+ } else if (strcmp(out->fuseArgv[i], "allow_other") == 0) {
+ PUSHARG("-o");
+ PUSHARG("default_permissions");
+ break;
+ }
+ }
+ }
+
  // sanity check
  if (out->isDaemon && (!isAbsolutePath(out->mountPoint.c_str()) ||
  !isAbsolutePath(out->opts->rootDir.c_str()))) {